U.S. Pat. No. 5,352,096 discloses an air compressor A1 for automobiles which is fixedly mounted on a cylinder by a connector A2. The connector A2, a diaphragm A4, a main body A5 and two conducting members A6 are fixedly kept in place by a ring member A3. Within the cylinder is mounted a piston A7 which receives a spring A8 and has a protuberance on which is fitted a circular conductor A10. The position of the spring A8 is regulated by an adjusting rod A9.
However, the diaphragm A4 will lose its resiliency under a high pressure. Therefore, it is an object of the present invention to provide an improvement in the structure of a power breaker for a compressor for automobiles which can obviate and mitigate the above-mentioned drawbacks.